1. Field of the Invention
The present invention relates to soil stabilization methods and more particularly pertains to a new method of stabilizing soil for providing an effective and predictable method for stabilizing large areas of soil having sections of soil of various compositions and slopes.
2. Description of the Prior Art
Large land contouring projects, such as, for example, golf course construction, typically involve the formation of a variety of land features or contours that are desirable for lending the golf course a distinctive character and making golf play more challenging. However, desirable land contours often produce a wide variation of slopes and curves which especially vulnerable to erosion, many times at varying erosion rates. Further, the wide land area typically encompassed by a project such as a golf course means that a wide variety of soil types and compositions may be encountered, and these varying soils will often exhibit different tendencies for erosion. While erosion control is very important during the soil placement and grading operations, it is critically important from the time that grading of the soil is finished until the time at which the turf is sufficiently established, such as, the time at which golf play may occur on the turf without damaging the turf. Thus, successful soil stabilization against erosion requires stabilization of the soil through the time that the turf is firmly established on the golf course and the turf is ready to be played on by golfers.
The possibility of erosion prior to turf establishment, and the relatively high cost of preventing such erosion until final turf establishment, is believed to have limited the extent of sloped areas of the contouring of golf courses, and the relative steepness of those sloped areas of golf courses heretofore designed and constructed. However, it is known that at least some golf course designers desire to exceed conventional contouring limitations and want to employ golf course contouring that exceeds conventional limitations on the steepness of sloped land areas and on the length of sloped land areas for enhancing the distinctiveness and difficulty of play the golf courses.
The use of various soil stabilization methods is known in the prior art. A highly popular approach to stabilizing soil during the turf grow-in period is to employ mats of fibrous grids laid out on the surface of the soil to hinder movement of the soil during rain showers and watering of the prepared surface of the soil. However, it has been found that erosion can still occur below the matting. Further, the cost of the matting is exceedingly expensive, especially in the quantities required to cover all of the areas typically needed to be stabilized against erosion on a typical golf course project, and the matting requires extensive labor to install. Although the matting is intended to eventually degrade into the soil over time, the matting is normally removed from the surface of the soil before the turf becomes fully established because of the belief that leaving the matting in place tends to slow or stifle turf growth.
Polyacrylamide, or “PAM”, has been known to be effective as a soil stabilizer, and insofar as is known, has been used on agricultural land in various manners. Amending soil with PAM has been shown to bond soil particles together, and also to facilitate the growth of vegetation in the soil by enhancing the root structure of the vegetation, by enhancing germination, by enhancing water retention, and by enhancing nutrient retention.
However, the use of PAM to amend soil in practical applications has been spotty, as the use of the PAM polymer has been very problematic. For example, use of too much of the polymer (at application rates of about 300 to 400 pounds per acre) can produce a hard crust on the top of the soil that actually hinders vegetation growth, and is expensive. Some agricultural use is known by injecting the PAM polymer directly into the water supply to irrigation systems in amounts of about one-half to one gallon per acre for spreading the PAM in a single uniform amount over an entire field of relatively level agricultural soil. The use of the PAM at these application rates has relatively little effect for holding the soil in place against any significant erosion forces, but is considered “safe” in that handling problems generally associated with the polymer are not encountered at these low application rates.
Another problem associated with PAM is that the polymer is exceedingly difficult to handle and use in the field, as the behavior of PAM in the presence of water can be extremely sensitive and unpredictable. For example, if the polymer is mixed with water in the wrong manner, such as too quickly or in too great amounts, the polymer (and the mixture with water) can easily become so highly viscous that mixing and application equipment can become clogged and unusable. On newly placed soil, especially where little or no compaction has occurred, the application of a PAM and water mixture to the soil can even precipitate erosion of the soil by the application process, especially on soil with a top surface having anything more than a minimal slope.
The method for stabilizing soil against erosion according to the present invention substantially departs from the conventional concepts and designs of the prior art, and in so doing provides an effective and predictable method for stabilizing large areas of soil of varying compositions and slopes.